﻿using System;
using System.Web;
using System.Text;
using System.Drawing;
using System.Drawing.Imaging;
using System.Web.UI;
using System.Drawing.Drawing2D;
using System.IO;
using MasApp.BLL;

namespace MasApp
{
    namespace Validate
    {
        /// <summary>
        /// 生成验证码的类
        /// </summary>
        public class ValidateNumber
        {
            public ValidateNumber()
            {

            }

            /// <summary>
            /// 验证码的最大长度
            /// </summary>
            public int MaxLength
            {
                get { return 10; }
            }

            /// <summary>
            /// 验证码的最小长度
            /// </summary>
            public int MinLength
            {
                get { return 1; }
            }

            /// <summary>
            /// 创建验证码的图片并输出
            /// </summary>
            /// <param name="containsPage">要输出到的page对象</param>
            /// <param name="validateNum">验证码</param>
            public void CreateValidateGraphic(Page containsPage, string code)
            {
                MemoryStream stream = this.getImgStream(code);
                //保存验证码到session
                SessUtil.setValidateKey(containsPage.Session, code);

                //输出图片
                containsPage.Response.ContentType = "image/jpeg";
                containsPage.Response.BinaryWrite(stream.ToArray());
            }

            /// <summary>
            /// 创建验证码及图片并输出.
            /// 长度为4的验证码尺寸为：50*22.5
            /// </summary>
            /// <param name="context">要输出到的context对象</param>
            public void CreateValidateGraphic(HttpContext context, int length)
            {
                string code = this.createValidateString(length);
                MemoryStream stream = this.getImgStream(code);
                //保存验证码到session
                SessUtil.setValidateKey(context.Session, code);

                //输出图片
                context.Response.ContentType = "image/jpeg";
                context.Response.BinaryWrite(stream.ToArray());
            }

            /// <summary>
            /// 生成验证码图片并返回图片的MemoryStream
            /// </summary>
            /// <param name="validateNum">string the validate code string</param>
            /// <returns>MemoryStream of the validate image</returns>
            public MemoryStream getImgStream(string validateNum)
            {
                Bitmap image = new Bitmap((int)Math.Ceiling(validateNum.Length * 12.5), 22);
                Graphics g = Graphics.FromImage(image);
                MemoryStream stream = new MemoryStream();

                try
                {
                    //生成随机生成器
                    Random random = new Random();
                    //清空图片背景色
                    g.Clear(Color.White);
                    //画图片的干扰线
                    for (int i = 0; i < 25; i++)
                    {
                        int x1 = random.Next(image.Width);
                        int x2 = random.Next(image.Width);
                        int y1 = random.Next(image.Height);
                        int y2 = random.Next(image.Height);
                        g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
                    }
                    Font font = new Font("Arial", 12, (FontStyle.Bold | FontStyle.Italic));
                    LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height),
                     Color.Blue, Color.DarkRed, 1.2f, true);
                    g.DrawString(validateNum, font, brush, 3, 2);
                    //画图片的前景干扰点
                    for (int i = 0; i < 100; i++)
                    {
                        int x = random.Next(image.Width);
                        int y = random.Next(image.Height);
                        image.SetPixel(x, y, Color.FromArgb(random.Next()));
                    }
                    //画图片的边框线
                    g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
                    //保存图片数据
                    image.Save(stream, ImageFormat.Jpeg);
                    //输出图片
                    //containsPage.Response.Clear();
                    //containsPage.Response.ContentType = "image/jpeg";
                    //containsPage.Response.BinaryWrite(stream.ToArray());
                }
                finally
                {
                    g.Dispose();
                    image.Dispose();
                }
                return stream;
            }

            /// <summary>
            /// 生成验证码字符串
            /// </summary>
            /// <param name="length">验证码长度</param>
            /// <returns>验证码</returns>
            public string createValidateString(int length)
            {
                //合法随机显示字符列表
                string strLetters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ123456789";
                int letter_length = strLetters.Length;
                Random r = new Random();
                StringBuilder sb = new StringBuilder(length);
                //生成随机字符
                for (int i = 0; i < length; i++)
                {
                    sb.Append(strLetters.Substring(r.Next(0, letter_length - 1), 1));
                }
                return sb.ToString();
            }

            /// <summary>
            /// 生成验证码（纯数字）
            /// </summary>
            /// <param name="length">指定验证码的长度</param>
            /// <returns></returns>
            public string CreateValidateNumber(int length)
            {
                object[] randMembers = new object[length];   //随机生成的数字集合
                int[] validateNums = new int[length];  //抽取出来的随机数字集合
                string validateNumberStr = "";
                //生成起始序列值
                int seekSeek = unchecked((int)DateTime.Now.Ticks);
                Random seekRand = new Random(seekSeek);
                int beginSeek = (int)seekRand.Next(0, Int32.MaxValue - length * 10000);
                int[] seeks = new int[length];
                for (int i = 0; i < length; i++)
                {
                    beginSeek += 10000;
                    seeks[i] = beginSeek;
                }
                //生成随机数字
                for (int i = 0; i < length; i++)
                {
                    Random rand = new Random(seeks[i]);
                    int pownum = 1 * (int)Math.Pow(10, length);
                    randMembers[i] = rand.Next(pownum, Int32.MaxValue);
                }
                //抽取随机数字
                for (int i = 0; i < length; i++)
                {
                    string numStr = randMembers[i].ToString();
                    int numLength = numStr.Length;
                    Random rand = new Random();
                    int numPosition = rand.Next(0, numLength - 1);
                    validateNums[i] = Int32.Parse(numStr.Substring(numPosition, 1));
                }
                //生成验证码
                for (int i = 0; i < length; i++)
                {
                    validateNumberStr += validateNums[i].ToString();
                }
                return validateNumberStr;
            }

            /// <summary>
            /// 得到验证码图片的长度
            /// </summary>
            /// <param name="validateNumLength">验证码的长度</param>
            /// <returns></returns>
            public static int GetImageWidth(int validateNumLength)
            {
                return (int)(validateNumLength * 12.5);
            }

            /// <summary>
            /// 得到验证码的高度
            /// </summary>
            /// <returns></returns>
            public static double GetImageHeight()
            {
                return 22.5;
            }
        }
    }
}